Electrical controller



Jan. 16, 1923. 1,442,496

E. W. SEEGER. ELECTRICAL CONTROLLER. FILED APR. 13, 1922.

LNPTHVTOR.

ATTORNEY Patented am. 16, 1923.

UNITED STATES PATENT- OFFICE.

EDWIN W. SEEGER, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER- HAMMER MFG. 00., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- CONBIN.

ELECTRICAL CONTROLLER.

Application filed April-13, 1922. Serial No.552,297.

. To all whom it may concern:

Be it known thatI, EDWIN W. SEEGER, a citizen of the United States, residing at Mi].- waukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Electrical Controllers, of which the following is a full, clear, concise,and exact description, reference be ing had to the accompany ng drawing,/

forming a part of this specification.

This invention relates to electrical icontrollers and more particularly to the control of induction motors by means of fluid rheostats.

Fluid rheostats are commonly employed in the secondary circuit ofinduction motors for starting and speed regulating purposes but the usual type of fluid rheostat does not \function properly where it is necessary to The present invention has among its ohjects to provide a fluid rheostat controller for induction motors wherein provision is made for insuring proper resistance control of the secondary circuit of the motor for plugging. I

Another object is to provide a controller of the aforesaid character wherein provision is made for effecting a quick reduction of.-

the immersed area of the; electrodes of the rheostat and to insure against reversal of the power connections of the motor except upon reduction of such area to a given value. Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates schematically an embodiment of the invention which .will now be described, it being understood that the embodiment illustrated is susceptible of modification without departing from the scope ofthe appended claims. 1

I In the drawing 1 indicates a 3 phase induction motor to be su plied with current from lines L L and: E, the primary cirprovide for plugging of the motor. As is cuit of said motor being controlled by reversing switches 2 and 3 and the secondary c rcuit thereof being controlled by a fluid rheostat 4. Reversing switches 2 and 3 are of a conventional type and are adapted to be operated by a lever 9 through the medium of ashaft 10 having cams thereon for effecting closure of said switches selectively upon movement of said lever in opposite directions from an intermediate off position. Rheostat- 4 comprises a plurality of electrodes 11, an electrolyte chamber 12 for said electrodes and a displacement chamber 13 located below'said former chamber and in communication therewith. The level of the electrolyte within chamber 12 is controlled by air under pressure in displacement chamber 13 the air being supplied from any suitable source through a pipe 14.

The upper wall on displacement chamber 13 is provided with a valve 15 having a reciprocable operating rod 16 connected thereto said rod being biased upwardly by a spring 17 to efi'ect closure of said valve. The upper end of rod 16 co-operates with a cam projection 18 on operating-lever 9 and the arrangement is suchthat when said lever is in its oil position said cam serves to hold valve 15 in its open position and upon movement of said lever into either of its operative positions, said cam permits closure of said valve under the action of spring 17.

Operating lever 9 is adapted to be locked in off position by a reciprocable locking member 19, said member being biased towards said lever by a spring 20 and being adapted to engage a recess 21 therein. Locking member 19 is releasable against the action of spring 20 by a winding 22 adapted 15 closes and assuming that air is admitted through pipe 14 the level of the electrolyte in chamber. 12 is raised to decrease theresistance in the secondary circuit of the motor for starting. Upon raising of the electrolyte above the level indicated in the drawing, switch 23 is opened to de-energize winding 22 and locking member 19 is then yieldingly held against the hub of operating lever 9 by spring 20 to provide for locking of said lever upon return thereof to of]? position. Upon return of lever 9 to off position valve 15 is opened to permit a quick drop of the electrolyte in chamber 12 to'the level indicated in the drawing and upon dropping of the electrolyte to such level switch 23, closes to effect release of locking member 19. Thus during movement of operating lever 9 from one operative position into the other operative position for plugging of the motor said lever is momentarily restrained in off position until the immersed area of the electrodes is reduced to a given value.

It is apparent that otherv types of fluid rheostats can be employed than that shown in the drawing and that other means can be provided for effecting a'quick reduction in the immersed area of the electrodes for plugging. Also it is apparent that the invention is not limited tomanual control, but is also adapted for electromagnetic control.

W hat I claim as new and desire to secure by Letters Patent is}: q

1. In a controller for induction motors, in combination, means for establishing reverse power connections for the motor, a fluid rheostat for controlling the secondary circuit of the motor and means insuring against reversal of the power connections by said former means for plugging of the motor except upon a given immersion of the electrodes of said rheostat. j Y

2. In a controller for induction motors, in combination, means for establishing reverse power connections for the motor, a fluid rheostat for controlling the secondary circuit 0f the motor and means for increasing the immersed area of the electrodes of said rheostat for starting of the motor and for insuring quick reduction of such area to a given value prior to reversal of the power connections byLsaid former means for pluggmg of the motor. I

. 3.. In a controller for induction motors, in combination, means for establishing reverse power connections for the motor, a fluid rheostat for controlling the secondary of the -motor,-said rheostat including means for increasing the immersed area of the electrodes thereof for starting of the motor and means for effecting a relatively quick reduc-' tlon 1n the immersed area of the electrodes v prior to plugging of the motor, and means 4. In a controller for induction motors, in combination means for establishing reverse power connections for the motor a fluid rheostat for controlling the secondary circuit of the motor, said rheostat including means for increasing the immersed area of the elec trodes thereof for starting of the motor and means for effecting a relatively quick reduction in the immersed area of the electrodes upon interruption of the power connections and means for insuring against reversal of the power connections by said first mentioned means except upon a given reduction in the immersed area of said electrodes.

'5. In a controller for induction motors, in combination, a pair of reversing switches operable selectively to establish reverse power connections for the motor, a fluid rheostat for controlling the secondary circuit of the motor, said rheostat including means for eflecting a quick reduction in the immersed area of the electrodes thereof upon opening of either of said reversing switches, and means associated with said reversing switches for insuring against reversal of the power connections for-plugging of the motor except upon a given reduction in the immersed area of theelectrodes of said rheostat.

6. In a controller for induction motors, in combination, a pair of reversing switches for establishing reverse power connections for the motor, a fluid rheostat for controlling the secondary circuit of said motor, said rheostat including avalve for effecting a quick reduction in the immersed area of the electrodes thereof, an operating member for said switches adapted to open said valve upon opening of either of said reversing switches and means associated with said operating member for insuring against reversal of the power connections by said switches except upon a given reduction of the immersed area of the electrodes of said rheostat.

7. In a controller for induction motors, in combination, a pair of reversing switches operating means therefor including a member movable in opposite directions from an intermediate off position to effect closure of I said switches selectively, a fluid rheostat connected in the secondary circuit of the motor, means for effecting a quick reductionin the lmmersed area of the electrodes of said rheostat upon movement of said operating memthe motor, a fluid rheostat connected in the secondary circuit of said motor, means for closure of said reversing switches except operating said reversing switches selectively upon reduction of the immersed area of the and for ellecting a quick redaction of the electrodes of said rheostat to a given value. 10 immersed area of the electrodes of said rheo- In Witness whereof, I have hereunto substat upon opening of said reversing switches, scribed my name.

and an electro-responsive locking device controlled by said rheostat for insuring against EDWIN W. SEEGER. 

